1. Field of the Invention
The present invention relates to a data transfer system, and more specifically to a data transfer system capable of confirmation of data transfer between a paging terminal and a transmitter, both being interconnected with each other through a transmission line.
2. Description of the Related Art
Wide use is made of a selective call radio equipment called a "pocket bell", a so-called pager. When it is desired to call a person carrying such a pager, a telephone number peculiar to the pager is dialed, so that there comes a ringing of a calling sound or display of a simple message on a display window of the pager.
In prior practice of a data transfer system of a pager of the type described above, a radio paging terminal 21 includes a message data transmission circuit 1A, and a transmitter 20 includes a message data modulator section 2 and a transmitter section 3, the radio paging terminal 21 and the transmitter 20 being interconnected with each other through a transmission line 9. Message data received by the transmitter 20 is modulated by the message data modulator section 2, and is finally sent from the transmitter section 3 through an antenna 12. There is however no confirmation means to confirm whether or not the message data transmitted from 1A is correctly tranmitted in the form of radio waves.
The prior art data transfer system has such difficulty as described above because it includes no means to confirm whether or not the message data transmitted from the radio paging terminal is correctly received by the transmitter and hence it includes no means to correctly grasp the details of the preferred message data without improving the reliability of data transfer.